Don't you need to have different networks on your two default gateways in relation to the main one to avoid loop back again?
63.34.8.3 when accessing to public IP in the case of going to 10.5.2.2 will later be able to go to 10.5.2.1 ? are you sure?
if you are new setting mwa3 you can take a look here: [Solved] Mwan3 - MWAN Interface Live Status showing offline for all interfaces - #2 by braian87b